


A Merman and An Incubus

by Take_Me_To_My_Fragile_Dreams



Series: Collaborations, Prompts and Requests [8]
Category: Mortal Instruments Series - Cassandra Clare
Genre: Alec is a merman, M/M, Magnus is an incubus, Sex Magic, Tail Sex
Language: English
Status: Completed
Published: 2013-06-19
Updated: 2013-06-19
Packaged: 2017-12-15 10:55:35
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,894
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/848705
Author URL: https://archiveofourown.org/users/Take_Me_To_My_Fragile_Dreams/pseuds/Take_Me_To_My_Fragile_Dreams
Summary: <blockquote class="userstuff">
              <p>It starts in a Jacuzzi, with an incubus. The antagonist is a merman and the plot involves elements like the rough edge of a table as a counterpoint to pleasure and being desperate to fuck.</p>
            </blockquote>





	A Merman and An Incubus

**Author's Note:**

  * For [TheShhTiger](https://archiveofourown.org/users/TheShhTiger/gifts).



Blue eyes watched the creature across from him warily, tail flicking nervously in the warm water as Alec struggled not to touch the demon lounging just a few feet away from him. He was practically hugging the edge of the tub, tail curved so that his dorsal fins dangled over the edge, facing away from the other man. He could still defend himself if needed, the fins in perfect position for a good swipe at the incubus' face should he do anything Alec deemed inappropriate. Which was almost everything Magnus did as it turned out.

"Really, love, must you be so distrustful?" The demon purred, fixing slitted green eyes on the merman, his chin resting on his hand as he watched the other male. "I may be a creature of lust but I won't touch the unwilling." He paused, a slow smirk curving his lips upwards. " _Most of the time."_

Alec growled, scales flashing a deep blue as his fins slapped against the water in warning, sloshing liquid over the edge of the tub. " _Shut_ up. I don't even know why I agreed to this."

"Because of my superior charm?" Magnus offered, his own long and slender pointed tail dipping in and out of the water, leather wings fluttering into a more comfortable position.

Blue eyes rolled, a huff of exasperation leaving the merman's lips. "You are impossible."

"That's because you're resisting, precious." The incubus pointed out, fixing the other male with a steady gaze. "If you don't resist then you'll find out just _why_ my company is so sought out after."

"Meaning that if you weren't using your pheromones to seduce someone, they'd find you as insufferable as I do." Alec grumbled, drawing small patterns into the surface of the water with a sharp nail, webbed fingers glistening. "And I'm not resisting," He added, pale skin flushing as his scales flickered from various light blues to multiple dark hues. "There's nothing to resist. You're intolerable, why would I want you?"

Green eyes darkened, and Magnus chuckled, low and deep, sending chills up the merman's spine. "Are you sure about that now?"

His voice was like fingers stroking up Alec's spine, leaving the male shivering from the feeling, back arching slightly. "Why wouldn't I be?"

Magnus smirked, slow and sharp, canines bared as his eyes blazed with excitement. A sweet smelling scent hit the other male's nose and Alec's scales shifted into a deep blue, dark as the night sky. "Oh lovely," the incubus purred, tail waving slowly as it stretched out for Alec's, wrapping loosely around the narrow end, just above the other male's fins. "I'm going to make you regret saying that."

"Wha-" Alec sucked in a sharp breath, thrashing slightly as he was yanked underwater, the gills on his neck and rib cage allowing him to breathe in the few moments he was held under before he was pushed against the side of the tub, water falling down his face as he blinked up at Magnus in shock. "What the hell?!" He snarled angrily, hands forming into claws, prepared to wipe that smirk off of the demon's face before he hissed, tail thrashing when the strong grip of the incubus' hands on his wrists stopped him.

Magnus leaned closer, and Alec could smell the overwhelming sweetness on his breath. It was a thick, heady aroma that had the merman tilting his head up to get a better scent, an involuntary reaction that he just barely forced himself to stop doing. He jerked his hips up, struggling to find a way to get the incubus away from him.

Magnus pushed his forehead against Alec's, dilated green eyes flickering black as he stared into wide blue's. "Stop." He murmured and much to the merman's complete and utter disbelief, his body obeyed.

Alec snarled, baring sharp pointed teeth as his fingers curled and twisted, struggling to find a way to tear at the other male's skin.

"Be still." Magnus commanded, voice soft and soothing, as if he were calming a frightened animal. Green eyes gazed pointedly at Alec's hands which were now frozen in their earlier position and he smoothed a thumb over the clawed hands, pressing gently into the other male's palm as he moved his fingers over Alec's webbed ones, smoothing them into a more comfortable position.

"Stay." The incubus intoned, pressing a kiss to a pale wrist, small blue scales scattered over ivory skin. He trailed a tanned hand down Alec's cheek and any snarled insults the other male may have been preparing were stopped in the wake of tenderness that gleamed in Magnus' eyes.

"You're beautiful. Do you know that?" Alec blinked, stupefied at this sudden change in attitude. "I'm sure you do," Magnus continued, thumbing the skin below the merman's gills, just above his collarbone. "After all, I know the price someone would pay in order to have you as their own."

A small flash of fear jolted through Alec at that, his tail finding the strength to wiggle once more as his scales turned an icy blue.

"Shhh." Magnus soothed, petting the other male's tail gently, his own tail sliding slowly over wet scales, the warm leather surface surprisingly pleasant. "Hush, pretty one. I will not harm you."

Alec shivered, a soft croon leaving his lips at the touch. "I'm not an animal!" He finally managed to get out, blue eyes glaring up at the incubus.

"Of course not," Magnus murmured, hands moving to cup the merman's cheeks, thumbs rubbing soft circles. "you're far more precious than an animal." Soft kisses rained down on Alec's face and he shivered, breathing speeding up as Magnus moved painstakingly slowly, covering his neck and shoulders in loving kisses. Green eyes flickered up to the other male and an angry growl left Alec's throat when he saw the flickering black hidden within the green depths.

"Would you quit messing around?" He snarled, fins slapping the water in irritation. "I know this isn't how you normally treat your bedmates, I've seen more than enough of the aftermath to know that you're nothing like this." Blue eyes narrowed in suspicion, fingers twitching slightly. "Just what game are you playing at?"

Magnus' head dropped, shoulders shaking as he lifted a hand to his mouth, covering a wide grin. "My my, love, I didn't think someone like you would want it hard and dirty. I had thought you'd like it better this way but very well." His smile widened to a dangerous smirk, the soft heady scent turning darker and more seductive, reeking of danger and thrills as his eyes flickered from green to black and back. "I'll give you what you want."

Alec barely had time to gasp before he was being flipped onto his stomach, a weight placing itself on the dip of his back as sharp nails trailed teasingly down his skin.

"As beautiful as your tail is, I must insist that you shed it _now_." Magnus growled, bucking his hips sharply into the merman's scale covered rump, earning a gasp from the other male.

"And why should I?" Alec challenged, webbed hands clenching as they braced against the side of the tub.

A sharp laugh left the incubus' lips and then Alec was whimpering as dozens of invisible hands traveled over his body, stroking his scales, brushing over his gills and playing with pebbled nipples. "You _really_ don't want to question me." Magnus snarled, wings stretching out imposingly behind him. "Now get the tail _off_ or I'll leave you here with my magic and let it toy with you as it wishes. It's not like it matters, I still get something out of it either way."

As if to prove a point, Alec felt fingers stroke over his scales, toying with the place where skin faded to scales, one of his most sensitive spots.

Deciding to follow Magnus' orders, lest he go mad, tiny pin-pricks of pain intermingling with a ticklish sensation began to run up the sides of his tail and down his fins. The blue scales slowly melting into smooth, pale skin, and Alec lay there, waiting for the incubus to speak.

"Good boy," Magnus purred, rubbing at the dip of the merman's hips. "It seems you _can_ be obedient when you want to be."

Alec scowled, squirming slightly under the demon. "Would you stop treating me like a dog?" He huffed, barely concealing the heat in his voice.

"But it's so much fun watching you get worked up." The incubus purred, biting lightly at the merman's shoulder.

"You're a bast-" Alec gasped, flinching slightly as something wound around his leg. Blue eyes flicked back to see Magnus' tail waving slightly behind him, the soft leather-like surface sliding against his skin.

"Bastard or not, you'll soon be screaming my name either way." The demon purred, eyes dancing in amusement as he edged his tail forward, the slightly pointed tip flicking against the other male's entrance,

"You've got to be kidding me." The merman practically moaned, eyes wide in disbelief as his hips jumped.

"I don't kid when it comes to pleasure." Magnus purred, flipping the other male over. His fingers curled around Alec's wrists, pressing them against the tub as he took the merman's lips in a possessive kiss. "After all," He breathed huskily, eyes black as night as he licked his lips. "I'm hungry."

Alec let out a shocked moan as Magnus' tail surged forward, twisting its way into the male's body, warm and alive. His hips jerked, body twitching with each movement as his eyes squeezed shut. It didn't hurt, it barely even felt uncomfortable, and Alec had mere seconds to wonder if this was because Magnus was an incubus before the curved tip was brushing against his walls just right and his mind went blank.

"You're even more exquisite when in pleasure." The demon murmured, brushing his knuckles against his new lover's cheek as he continued to press his tail against that one spot, greedily soaking up the noises and expressions the other male made. He trailed a hand down, wrapping thin talented fingers around the merman's arousal, swiping lightly at the tip with a sharp nail.

Alec shuddered, a jolt of heat moving down his spine at the slight sting of the touch, hips jerking up into Magnus' hand. " _Magnus!"_

The incubus tightened his hand, a low growl leaving his lips at the sound of his name, eyelids sliding half shut. "Say it again." He demanded, waving the tip of his tail, rubbing against the other male's sweet spot.

The merman was hopeless to do anything but that as the demon's hand began to move. " _Ma-Magnus-please_ , Magnus-"

"Yes, precious?" He purred, dipping his head to lick teasingly at the other male's lips, tongue just barely brushing the merman's. Everytime Alec spoke his name a spike of heat went down his spine.

"Y-you know what I w-want-" The merman gasped, webbed hands moving to clutch at the demon's hips, holding his close.

"And you know what I want." Magnus murmured huskily, gazing into glazed blue eyes. "The question is, will you give us both what we desire?"

"I-" Alec trembled, breath hitching as his eyes slammed shut, hips squirming. "Y-yes, okay- God, just _please-_ "

The demon's smirk was victorious. "Finally." Magnus breathed, straddling the merman's hips, hand guiding the other male's arousal to his entrance. Any other person wouldn't be able to do it, would tear and bleed with the speed he was taking Alec's cock without preparation, but he was built for this, born to be filled, and barely even felt discomfort as he settled fully onto the other male's arousal, head tilting back as he let out a keening cry. His hands moved to the merman's shoulders, nails digging in slightly as he rocked against the other male, tail still twisting with in his lover.

"O-oh, god-" Alec panted, writhing slightly under the demon. He knew that being with an incubus was a rare feeling, that the way Magnus' body felt and the things he could do had made many a human willingly go to their deaths in his bed, but this... this was exquisite. Indescribable. _Breathtaking_.

It wasn't just the way the demon felt, all tight walls and hot body, it was the way Magnus looked. It was the look on his face as his eyes slammed shut in pleasure, lips parting in moans and whimpers as he rolled his hips wantonly. It was the way he seemed afraid to part, pressing as much of his body against Alec's as he could, wings outstretched behind him, the curved tips fluttering. And it was the way he looked at the merman, black eyes dazed with pleasure, green and gold flecks flickering in and out of the darkened iris' as Magnus cried out his name, moving eagerly against his body.

It was that strange vulnerability that Alec saw in the incubus when he was most in his element that had the smaller male wrapping his arms around Magnus, pulling him closer and burying his face in a tanned neck. "Magnus..." He breathed into the demon's ear, nipping at his lover's ear.

The other male shuddered, moaning loudly as he leaned into the touch, hips moving all the faster. "Cum." Magnus demanded, moving his tail faster as he tightened around the merman, hunger thrumming through his body.

Alec obeyed the command willingly, muffling his shout of pleasure into his lover's shoulder as his body shuddered, hips jerking slightly as his eyes slammed shut, spots dancing across his vision.

At the feel of being filled Magnus threw his head back, keening loudly as he rocked against the other male, eagerly taking what the merman was giving. The hunger was like an itch he couldn't scratch, driving him insane as he writhed on top of Alec. He needed more, he needed to be filled over and over again, he needed-

"Magnus-" Alec breathed, squirming underneath the incubus' undulating body. "Magnus, _god-_ "

The incubus jerked up, yanking the other male with him as he staggered out of the tub, panting harshly as he trembled.

"Magnus, what-" Alec sucked in a sharp breath as he slammed into the wall, blinking disorientedly as he looked up at the demon, blue orbs widening at the sight.

" _You_ , are driving me insane." The incubus hissed, yanking the merman against his body. "I'm hungry, dammit." He growled, biting sharply at the other male's neck. "So stop torturing me and let me get us somewhere where my skin won't prune up otherwise I'm going to end up riding you on the floor and I will _not_ be happy. Understood?"

Alec nodded shakily, eyes glazing slightly as the sweet scent of the demon hit him full force. "Y-yeah."

"Good." Magnus growled, tail flicking behind him as he grabbed a webbed hand, yanking the merman towards the door. "Now lets go. I want you to fuck me again."

The male let out a disbelieving laugh in reply.

* * *

"I'm start- _fuck!-_ starting to understand how someone could die from this." Alec gasped, sweat running down his face as Magnus rocked against him, looking completely wrecked as he whined, head tossing and body writhing.

"Oh sh-shut up." The demon snarled, flashing sharp canines. "You'd understand if you could feel this hunger. It's like a piece of you is empty and no matter what you do to fill it up there's just too many holes and it never gets you anywhere."

"Then why keep trying?" The merman questioned, jerking his hips up into his lover, hands gripping Magnus' hips tightly as he ignored the uncomfortable feeling of the table rubbing against his back, the pleasure greater than the discomfort.

"The same reason mortals look for love." The incubus growled, leaning down to steal the other male's lips. "Now less talking, more fucking."

"Yes, sir." Alec murmured teasingly, voice breathless as he met Magnus' lips greedily.

* * *

"Alexander, if you keep acting like that I might begin to think that I've killed you after all." Magnus murmured in amusement, tracing designs into the merman's back.

"You refused to stop for three. _days_." Alec groaned, letting out an exasperated sigh. "I may not be human but I need breaks too, you know."

"It could have been much longer." The demon mused. "I once went several weeks joined with a vampire. Of course, after that I couldn't stand the sight of her."

The other male's nose wrinkled. "I didn't need to know that."

Magnus chuckled, pressing a kiss to his lover's neck. "Of course you didn't, pretty one."

Alec rolled over, stretching slowly as he peered up at the demon. "I feel like a jellyfish." He accused, blue eyes narrowed.

The incubus burst into laughter. "You're too cute, I hope you know that."

The smaller male blushed, huffing softly. "I don't like you."

Magnus grinned. "Whatever you say, precious."

"I don't." Alec insisted.

"Mmm hmm."

"I _don't_!"

"Go to bed, love."

"..."

"Good night, Alexander."

"It's morning actually."

"Good morning then."

"You're insufferable." Alec huffed, wrapping an arm around the incubus.

"And you're adorable." Magnus answered, cuddling against the merman, body sated for now. "Especially when you blush." He added, grinning widely.

"Whatever." Blue eyes rolled. "Just go to bed."

"Will do~" The demon purred, tail flicking slowly like that of a pleased cat. "And Alexander?"

"Mmm?"

"I look forward to our next escapade."

Alec sputtered.


End file.
